Esketamine and Perioperative Depressive Symptoms

Inclusion Criteria: * Patient undergoing elective major surgery * Ages between 18 and 65 years old * Moderate to severe depressive symptoms ( the Patient Health Questionnaire-9 scores equal to or more than 10 and Montgomery-Åsberg Depression Rating Scale scores equal to or more than 22 ) * Signed informed consent Exclusion Criteria: * had aphasia or any conditions that prevented mental health assessments, * had a history of psychotic or bipolar disorder, * had a comorbidity that affected hormone levels, * required prolonged postoperative mechanical ventilation, * had received treatment with antidepressants within 2 weeks prior to the screening, * had a body mass index greater than 30 kg/m2 and a Child-Pugh score greater than 6 points. * had made repeated suicide attempts (as assessed by the 12-item Quick Inventory of Depressive Symptomatology scores less than 3), * had experienced adverse reactions to ketamine or esketamine, * had known drug use disorders, * pregnant or breastfeeding